I. Field of the Invention
This invention relates generally to discharge devices for pressurized fluids such as devices used for facilitating the discharge of liquid aerosols and certain fire extinguishers. More specifically, this invention relates to a method and apparatus for significantly improving the discharge efficiency and effectiveness of such devices by conditioning the discharge stream of the device during discharge.
II. Prior Art and Other Considerations
An important aspect of containers for dispersing liquids under pressure is the ability of the device to effectively discharge and place its active ingredients at desired locations and over a desired area of treatment in an appropriate concentration or density necessary to accomplish the desired function or task. This ability is of critical importance with regard to fire extinguishing units and is of special importance in liquified-gas type fire extinguishers. Prior art fire extinguishers of the liquified-gas variety typically contain either liquid carbon dioxide or liquid Halon as the extinguishing agent. These fire extinguishing agents are maintained in liquid form, under pressure, until discharged from the container. Typically, compressed nitrogen or another similarly inert gas is used to pressurize the vessel. However, these pressurizing mediums have a tendency to dissolve with the dispersement liquid sometimes causing the liquid to be discharged in a more gaseous than liquid state. Halogenated agents, such as Bromochlorodifluromethane (HALON 1211), Bromotrifluoromethane (HALON 1301) and mixtures of HALON 1211 & 1301, have been used for many years and are highly effective as fire extinguishants for virtually all classes of fires. However, these agents have been included in the Montreal Protocol list of controlled substances and are scheduled for discontinuance in the near future. Replacement agents are being investigated and tested, however, discharge problems which have plagued the aerosol and pressurized liquid industry for years continue to be a problem with the proposed replacement agents. One of the typical problems associated with this industry has been oscillating, uneven, sometimes liquid--sometimes gaseous, discharge streams. This phenomenon is commonly referred to within the industry as "chugging" and can seriously effect the efficiency and effectiveness of liquified-gas fire extinguishers and other aerosols. Chugging occurs when too much of the propellant medium, such as nitrogen, becomes dissolved within the liquid agent to be dispersed thereby creating an uneven flow of the liquid agent and a more gaseous discharge. A smooth, less gaseous, flow has been found to significantly improve the fire fighting effectiveness of liquified-gas type fire extinguishers.
A continuing need exists, therefore, for the provision of method and apparatus which will effectively reduce the amount of dissolved propellant within the discharge stream of a pressurized fluid discharge vessel during discharge thereby providing for a smooth, less gaseous flow of liquid agent from the vessel. The present invention provides method and apparatus which can be used with virtually any pressurized liquid dispersement device to condition the discharge stream of the device thereby significantly improving its efficiency and effectiveness and eliminating the unwanted "chugging" characteristics associated with the prior art.